Use

Heimdall can be use to process filterbank data from 2 formats:

• Sigproc Filterbank Files
• PSRDada Ring Buffers

After Compiling a command-line applicaiton named heimdall will be built, as well as some other utiliities. The command line options for the heimdall executable can be displayed by running heimdall -h and is shown below:

Usage: heimdall [options]
-k  key                  use PSRDADA hexidecimal key
-f  filename             process specified SIGPROC filterbank file
-vVgG                    increase verbosity level
-yield_cpu               yield CPU during GPU operations
-gpu_id ID               run on specified GPU
-nsamps_gulp num         number of samples to be read at a time [262144]
-baseline_length num     number of seconds over which to smooth the baseline [2]
-beam ##                 over-ride beam number
-output_dir path         create all output files in specified path
-dm min max              min and max DM
-dm_tol num              SNR loss tolerance between each DM trial [1.25]
-coincidencer host:port  connect to the coincidencer on the specified host and port
-zap_chans start end     zap all channels between start and end channels inclusive
-max_giant_rate nevents  limit the maximum number of individual detections per minute to nevents
-dm_pulse_width num      expected intrinsic width of the pulse signal in microseconds
-dm_nbits num            number of bits per sample in dedispersed time series [32]
-no_scrunching           don't use an adaptive time scrunching during dedispersion
-scrunching_tol num      smear tolerance factor for time scrunching [1.15]
-rfi_tol num             RFI exicision threshold limits [5]
-rfi_no_narrow           disable narrow band RFI excision
-rfi_no_broad            disable 0-DM RFI excision
-boxcar_max num          maximum boxcar width in samples [4096]
-fswap                   swap channel ordering for negative DM - SIGPROC 2,4 or 8 bit only
-min_tscrunch_width num  vary between high quality (large value) and high performance (low value)

To test heimdall on a Sigproc filterbank file, with the default parameters, ensure you have access to a server with an NVidia GPU, and:

1. Download a filterbank file with a transient pulse in it from the Swinburne Parkes FRB Data Portal (e.g. FRB110220 / fil_files / 03 / 2011-02-20-01:52:19.fil)
2. Run heimdall on this file with the default search options: heimdall -f 2011-02-20-01:52:19.fil
3. Combine the output .cand files into a single file for this beam: cat *.cand > beam01.cand

The colums of the .cand files are:

1. Detection SNR
2. Candidate Sample Number (for highest frequency channel)
3. Candidate Time (s)
4. Boxcar Filter Number (e.g. 3 equates to 2^3 or 8 samples)
5. Dispersion Measure Trial Number
6. Dispersion Measure (in pc cm^-3)
7. Members (the number of individual boxcar/DM trials that were clustered into this event)
8. First sample that the candidate spans
9. Last sample that the candidate spans

Inspection the cumulative output from the heimdall in beam01.cand, and sorting via SNR, you should find the line in the file with following values, which corresponds to the FRB in this file

51.4261 3267104 209.095 6   1176    944.746 909 3267056 3267280